Rioting began on Friday when the prison, which houses at least 5,000 inmates, caught fire, according to residents living near the prison. Police used tear gas to stop the protest. The cause of the fire is still under investigation.

"This morning at about 9 a.m., prisoners started rioting but within one hour we managed to stop it," Hillary Sengabo, spokesman of the Rwanda prisons, told reporters outside the prison.

"Only tear gas was used. No bullets. Even if some of them might be in need of blankets or other utensils, rioting is not a solution."

Riots are rare in Rwanda. The United Nations Special Rapporteur on the Rights to Freedom of Peaceful Assembly and of Association has in the past described Rwanda as a nation where protests are not allowed.

"It was like 200 people throwing stones at the same time and when the riot police arrived, they kept throwing stones," Henriette Uwase, who lives near the prison, told Reuters.

"They were hurling stones over there and it looked like hundreds of stones being thrown. You can see it, the window and door glasses have been smashed," said another resident, who did not wish to be named.

A Reuters witness saw police officers enter carrying handcuffs as authorities were questioning the prisoners. The media were not allowed to enter the prison.

President Paul Kagame is widely admired for restoring stability to Rwanda after its 1994 genocide, presiding over rapid economic growth and creating a relatively corruption-free government. But rights activists say those achievements have come at the expense of civil liberties.